Transmitting digital data over wireless connections can sometimes include transmitting data that has been corrupted in some way. Such corruption can come in the form of or be caused by noise in the link or channel, by interference from other transmissions, or by other factors. This problem can be exacerbated in systems that transmit data at high data rates. To deal with corruption issues, some transmission systems employ hybrid automatic repeat request (ARQ) or H-ARQ schemes. Such schemes provide an opportunity for data that has been corrupted to be retransmitted when such corruption has been detected by a receiver.
In H-ARQ schemes, a receiver that has received corrupted packets has an opportunity to receive a retransmission of the packets that have been corrupted. Once the retransmitted packets have been received, the receiver can combine the newly-received packets with the previously corrupted packets in an attempt to decode the packets to find an accurate representation of those packets. Thus, coded bits corresponding to a corrupted packet are stored and combined with coded bits from a subsequently received corresponding packet in an attempt to increase the likelihood that the packet can be correctly decoded.
Use of H-ARQ schemes can provide signal sensitivity gain through this combination mechanism. This can, in turn, enhance a system's throughput in a multi-cell environment.